At present, electric tools, such as an electric drill or an electric screw driver, include an electric motor and a trigger switch. The trigger switch has a trigger which is to be operated by a user; and the trigger switch can generate different signals in correspondence with the positions of the trigger when the user causes the trigger to move. For example, the electric motor is caused to be driven via use of a driving signal which has a duty ratio in correspondence with the signal of the trigger switch.
It is common that the trigger is pressed to move fast by the user when the user wants to activate the electric motor. In this condition, the duty ratio of the driving signal increases rapidly. When this occurs, the current of the electric motor may increase too fast, and the current impact on the electric motor may decrease the service life of the electric tool.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.